This invention relates to a cell. More particularly, this invention relates to a cell having a high drain and an enhanced eff:ciency measured in watt-hours per pound.
In any battery or cell, the amount of electricity produced is dependent on a number of factors. One of these factors involves the cathode. The cathode is composed of an electronegative material associated with an electrically conductive support. Thus, the electric power capable of being produced (watt-hours) from the cell is related to the amount of electronegative material associated with the electrically conductive support.
A factor which influences the current produced by the cell is the solvent for the electrolyte. The speed of ionic migration in the electrolyte solvent will determine the rate of electrical output. In order to have a high drain cell, an electrolyte solvent should be used which will permit a high rate of ionic migration of the electrolyte ions. Further, it is also important that the electrolyte solvent not leach material from the cathode.
A cathode must perform two functions. First, the cathode must provide the electron-transfer half-reaction, the other half-reaction being provided by the anode. Second, the cathode must transport into and distribute electrons within itself during discharge of the cell in order to be an effective cell.
A cell which contains a polyacetylene cathode offers many advantages. Although the polyacetylene cathode performs both of the functions set forth above, it has been found that the polyacetylene cathode will, with the passage of time, suffer from a diminished ability to transport into and distribute electrons within itself during discharge of the cell (i.e. loss of electrical conductivity). When this happens, the effectiveness of the cell is diminished.
For some electrical applications, such as an electric automobile, because of the weight of the object to be activated by a cell, the watt-hours per pound of cell is a critical factor and the drain rate is also a critical factor. The electrical conductivity stability of the cathode is, however, important for all electrical operations.
Polyacetylene and p-doped polyacetylene and their methods of preparation are described in the Journal of Polymer Science, Volume 12, pages 11 through 20, Shirakawa, et al (1974); Trans. Faraday Society, Volume 64, pages 823 through 828, Berets, et al (1968); in a paper presented at the Advanced Study Institute on the Physics and Chemistry of Low Dimensional Solids--Tomar, Portugal, Aug. 26-Sept. 7, 1979, and entitled Organic Metals and Semi-conductors: The Chemistry of Polyacetylene, (CH).sub.x, and Its Derivatives, MacDiarmid and Heeger; and in an IBM review paper presented at San Jose, California, April 1979, and entitled Organic Metals and Semi-conductors: The Chemistry of Polyacetylene, (CH).sub.x and Its Derivatives, MacDiarmid and Heeger. The disclosure of these papers are incorporated herein by reference. It is known, from these papers, that polyacetylene is minimally electrically conductive and that the electrical conductivity of polyacetylene may be increased by p-doping.
U.S. Pat. No. 3,907,597 is directed to a non-aqueous cell having an anode such as lithium, a cathode such as fluorinated carbon or copper sulfide, an electrolyte such as lithium perchlorate, and an electrolyte solvent such as sulfolane, or 3-methylsulfolane plus at least 20% by volume of a cosolvent which is mandatory and which reduces the viscosity of the sulfolane or 3-methylsulfolane. The '597 patent also discloses electrolyte solvents such as propylene carbonate, ethylene carbonate, gamma-butyrolactone, ethylene glycol sulfite, and dioxolane. This patent also teaches, that it is practically impossible to predict in advance how well, if at all, a non-aqueous electrolyte (meaning sulfolane and the other solvents set forth above) will function with a selected anode-cathode couple. The '597 patent further discloses that the parts of one cell (cathode, anode and electrolyte) are not predictably interchangeable with parts of another cell to produce an efficient and workable cell. The '597 patent fails to teach or suggest a cell having a cathode which is a mixture of polyacetylene and an electrically conductive material.
It is an object of this invention to provide a superior cell having a polyacetylene containing cathode with stable electrical conductivity properties.
An additional object of this invention is to provide a cell having a high drain rate.
Another object of this invention is to provide a cell having an enhanced efficiency as measured in watt-hours per pound of cell and a high drain rate.
Other objects and advantages will become apparent from the following more complete description and claims.